Leak tester for therapeutic masks



y 1947- J. A. HEIDBRINK ,420, 72

LEAK TESTER FOR THERAPEUTIC MASKS Filed June 29, 1944 2 Sheets-Sheet l INVE/YIUR Jag A He/q'brmk FFCE 9 Claims.

My invention relates to a leak tester for therapeutic masks as worn, and has for its object to provide a leak tester of the expansion type, wherein a weighted bellows-like gas container will be held closed by normal air pressure unless as is admitted through an opening connected with the mask upon the face of a wearer, in which case the weighted rubber member will expand. thus indicating that there is a leak about the gas mask as it is worn upon the face of any person.

In this type of tester two fitting frame members are applied to one another in such manner that the bottom member may move by gravity away from the top member. Ordinarily these frame members are circular in cross-section and the upper frame member is provided with a seat to which may be removably secured gas tight the inhalation tube of a gas mask opening into the chamber formed between the two frame members.

A bellows-like gas container circular in crosssection and open at both ends has one open end edge secured in gas-tight relation to the upper frame member and another open end edge secured gas-tight relation to the lower frame member. When this has been done, if the wearer of the mask inhales, negative pressure will be set up in the mask and in the inside of the bellows-like member so when the wearer of the mask holds his breath, external air pressure will hold the two parts closed. If, however, there is leakage about the mask as it is worn upon the face of the wearer, the air will force in, overcoming the negative pressure and permitting the bellows to expand and the bottom member to drop away from the top member. The rate at which this expansion and dropping takes place will give a degree of indication of the extent of the leakage about the mask as worn.

A serious difficulty has been encountered in securing the edges of the bellows-like member in a leak-proof junction with the respective upper and lower frame pieces. It is, of course, absolutely essential that this union be leak-proof and at the same time it is important also that the bellows, if possible, be readily removable from the frame members. Efforts have been made to effect this sealing by the use of adhesives, but this has been proved ineffective for several reasons. One is, of course, that sealing by adhesives is permanent and does not permit the removal of the bellows member for proper cleaning. As the member is used succcessively by many persons, particularly in connection with military aviation,

it must be frequently cleansed and sterilized, and cleansing of it and of the frame pieces can be efiected better when. the bellows has been removed.

A second difliculty with the use of adhesives has come from the fact that due to the flexing of the bellows member there is a tendency for the adhesive to loosen and permit leakage past the edges of the bellows member. There is also separation and tearing of the bellows member which may come from breaking down of the adhesive and a resulting loosening of the union thereof with the frame members.

It is a principal object of my invention. to provide non-adhesive means for uniting the edges of the bellows member with the frame members so at the same time there will be a gas-tight union between the same and yet the bellows member may readily be removed from the frame members.

It is a further object of my invention to provide the edges of the bellows members with annular beads or laterally projecting portions adapted to be engaged by the edges of annular ring members which may be held in a position to compress the bead and the adjacent annular portions of the bellows member.

It is a further object of my invention to provide annular channels in the two frame members of the same circumferences and facing one another when the frame members are brought together and to have the edges of the bellows members extend into these annular channels and be removabl clamped in gas-tight relation therein.

It is a further object of my invention to insert clamping rings in said annular channels and provide cooperating means on the rings and on one wall of the channel to hold the rings in position to compress the edges of the bellows member and thereby hold the bellows member in the channels in a gas-tight connection with the frame members.

It is a further object of my invention to form the annular channel with a pair of annular ribs extending laterally from the respective bases of the two frame members.

It is a fur her object of my invention to form one of each set of said annular ribs so as to extend outwardly from the. said base walls a distance greater than the other annular rib of said set, and, to provide an annular groove facing the annular channel in said greater extending rib,

It is a further object of. my invention to form clamping rings with a series of. projections thereon, preferably having walls sloping toward the upper margin of the ring and adapted to enter said annular groove in one of the walls of the annular channel and snap into position to hold the ring against the annular bead or projection of the bellows member so as to seal it gas-tight to the respective frame members and yet so that it may readily be withdrawn therefrom.

It is a further object of my invention to form the rings with an outer circumferential body and an inner flange of less thickness than the body, and to form this flange into a series of segments by cutting a series of transverse slots across them.

It is a further object of my invention to mount in the socket for connection with the tube of the gas mask a pin which is rigidly attached to the bottom frame member and extends centrally through the opening for connection with the mask tube and to form said pin with a head and an annular groove in the plane of the top of the upper frame member when the two members are held together, and to provide a swinging cover pivoted to the outside of the top base member with a slot therein adapted to enter the groove on the pin, in association with a detent for holding the same in closed position whereby the parts are permanently held together and the opening for the breathing tube connection is substantially closed.

The full objects and advantages of my invention will appear in detail in the following specification and the novel features by which the above noted advantageous results are obtained, will be "particularly pointed out in the claims.

Fig. 6 is a sectional view taken on line 66 of Fig. 1 and reproduced double size for better showing of details, with the frame parts in closed non-expanded position.

Fig. 7 is a transverse sectional view similar to Fig. 6 but with the breathing tube connected and the lower frame member dropping down. showing expansion of the bellows member from leakage of gas thereto, all parts being double size.

Fig. 8 is a side elevation view of the connector on the end of the breathing tube.

Having reference to Fig. 1, the top frame member H! is provided with a top circular base portion II through which extends an opening I2 surrounded by an annular cut-out portion forming an annular ledge I3, Figs. 1 and 6. The opening I 2 is tapered to anarrower point It at the bottom thereof, which overlies a cut-out portion l forming an annular ledge Hi, all as best shown in Fig. 6.

Referring to Figs. 2 and 6, the bottom member I! comprises a, base portion l8 having an annular upturned rib l9 about its outer margin. Centrally located upon the base portion [8 is an upstanding peg 2!) formed with a head M at its too and having an annular groove 22 about the bottom of the head. The peg 2B is seated within an opening 23 at the center of base I8. The base plate I! of the top member m is provided with an annular depending flange 24, cut out annularly at its bottom so as to leave a supplemental flange 25, Figs. 6 and 7. The annular flange I 9 fits in the cut-out portion 26 of flange 24, thus holding the parts united when the bottom is presented to the top. In such position the peg 20 extends up through the center of the opening [2 for receiving the connection to the breathing tube.

Upon a support 21 extending into the base I! of the top piece H1 is pivoted a latch member 23, Figs. 1 and 6. This latch member has a curved slot 29 and a finger piece 39. By means of the finger piece the latch 28 may be swung about so as to bring the edges of the slot as into the groove 22 of pin 20 which will lock the parts together. A projection 38' on the latch lever 28 is adapted to snapinto a depression ill on base member H to hold the parts in assembled position.

Spaced inwardly from the annular wall 24 is a concentric annular wall 32, depending from the base member H. Correspondingly positioned on base member i8 is a similar annular wall 33. These walls, taken in conjunction with the annular wall 24, when the parts are in the closed position of Fig. 6, form an annular space 34 which opens into an annular channel 35 between the adjacent edge of the annular walls 32 and This annular channel, also when the parts are in closed position, forms a circular chamber fit into which extends the opening 2 for connecting with the breathing line.

Along the periphery of chamber 36 extends an annular rib 37 from base H, and an annular rib 38 from base it, these annular ribs being of the same diameter and fronting each other so that in the closed position of Fig. 6 the form between their adjacent limits an annular passageway 39. Fig. 6. The ribs 37 and 38 are of less height than the ribs 32 and 33, so that passage 39 between them, connecting with passage 35, is wider than passage 35. Between ribs 32 and 31 is an annular channel 0 and between ribs 33 and 38 is an annular channel ll. These channels 40 and ll front each other and constitute a seat for the edges of the rubber bellows member which will now be described.

This bellows member 52 comprises a continuous wall '23 adapted to be folded into the chambers 34 and 36. In practice there is a single fold 45 in chamber 34 and double folds 46 and 4! in chamber The rubber bellows member 42 is preferably circular in all of its cross-sections and is open at both ends, being surrounded by a circular edge 48 on one side and a circular edge 49 on the other.

Adjacent the edge 48 is a transversely extended bead or projection 50 and adjacent the edge 49 is a similar bead or projection 5|. The respective projections 59 and 5! are of substantially the same area in cross section and are adapted to fit into the bottoms of the annular grooves 48 and M respectively, as clearly shown in Figs. 6 and '7.

A ring-like member 52, shown in detail in Figs. 4 and 5, is provided with an annular head portion 53 with a somewhat pointed annular end 54, which is adapted to engage the extension 50 at the upper edge 48 of the bellows member 43 when the ring member 52 is properly positioned. The cylindrical walls 55 of the ring member 52 are provided with transverse cuts 56, Fig. 5, dividing this cylindrical portion into sections 51, as indicated in Figs. 4 and 5, and in dotted lines in l. The ring 52 is made'of spring material 'so "each of the sections 5's is in effect a short and strong spring.

annular ring 6!, in all respects identical with the ring 52 is adapted to be introduced into the annular channel it between annular ribs 33 and 33, as shown in Figs. 6 and 7. The walls 32 and '33 are provided on the outer arcs thereof, as shown, with an annular groove 58, Fig. 7 having a "straight right-angled wall 59 facing away from the head '53 and having a sloping wall 6i? running into the said straight wall, as clearly shown in iFig. '7.

Upon the spring segments 5? of rings 5i. and 6! are formedprojecting ribs 62. These ribs are, of course, arcuate between pairs of slots at and areformed with sloping faces 62! and right-angled. arc'uate faces fi l. These faces are complementary to the faces 59 and to of the annular grooves 52 in the walls 32 and 33. It follows that when the rings "52 o iii are forced upon the annular extensions 56 and 5!, respectively, at the edges or the bellows member 42 within the annular channels M and ii, the several arcuate projections or ribs 5? will snap into the grooves 58 to bring the right-angled faces 6d of the ring projections against the right-angled faces 59 of the grooves 58, thus locking the rings within the slots Ml and 41.

This will have compressed the annular projectionsfifl and 5! in said grooves, particularly at the point 54 of the annular head portion 53 of the rings. This compression will effect a gas-tight sealing of the edges 48 and .5 and annular projected portions 50 and is! of th bellows member 42 upon the separable frame members. The edges of the rings 52 and ti extend beyond the outer limits of the annular walls 32 and 33, as indicated at 65, Figs, 6 and 7. This gives a finger hold at the top of segments El, enabling the successive release of these segments to withdraw the clamping rings and release the bellows to permit its withdrawal from the annular channel at and 4|.

From the above it will be seen that the edges about the open ends of the bellows member .2

may readily be clamped in gas-tight relation upon the respective upper member '5! and lower member I8 and that with substantially equal facility these edges may be released to permit removal of the bellows member.

The opening H for receiving the connector of the mask inhalation tube 556 has a conical inside wall 61, Figs. 6 and 7, extending to an annular ledge 68. The connector member 553 to which the inhalation tube es is attached, as indicated in Figs. 7 and 8, has secured about the outside thereof a rubber gasket it above a series of spring fingers H, which lie in a conical surface corresponding somewhat to the conical surface 61 of the opening 2. The spring fingers H are provided with outward arcuate bulge i2. When the connector is forced-into the opening 52 the spring fingers engage the conical wall 51 of the opening I2 and yield until they come past the ledge 68 when they snap in beneath that ledge and hold the connector attached to the member I I with the rubber gasket It compressed upon the ledge It, thus effecting a gas-tight seal between the inhalation tube 66 of the mask (not shown) and the space 35 inside Of the rubber bellows membe 42. This insures that no leakage of air or gas can get inside of the bellows member except from the breathing chamber, of the mask, and such leakage would necessarily have to come 6 past the :face corftacting surface of the mask or the exhalation valve.

In use, the mask to be tested is adjusted to the face of the wearer. The opening I2 is cleared by swinging the closure latch 28 into the position of Fig. 1, the parts being held together by the hand. The inhalation tube 66 is then connected with the upper base member I l of the tester in the conical-walled hole I2 for that purpose. The subject 'inhales to establish negative pressure in the mask, the inhalation tube, and the chamber and passages within the rubber bellows member 42. Then, holding the upper frame base H in the hands in a position so that gravity may act vertically upon the lower base member l8 and parts connected therewith, and holding his breath, the subject releases the lower base member i8 and its parts. If there is no leakage, external air pressure, because of negative pressure within the system, will continue to hold the parts together. If there is leakage, incoming air will first eliminate the negative pressure within the system and then will pass down into the cha l-- ber formed within the bellows member, and the lower base ill will move away from the upper base ii. If this movement is very slow, it will indicate that there is but slight leakage. If the movement is relatively rapid, it will indicate that there is extensive leakage. And the degree of leakage will to a considerable extent be determined by the rapidity of movement of the lower base member 13 from the upper base member I l The advantages of my invention will be apparent from the foregoing description. The primary advantage comes from the means for connecting the rubber bellows member to the separable upper and lower frame pieces of the tester in such manner that while the connector is gastight it may readily be freed to remove the rubber bellows member for cleaning and sterilization.

-A further great advantage is that the sealing effect by the means above described can not be broken by use, but will be continuously permanent unless and until it is desired to remove the conheating rings for the purpose of removing the rubber bellows member.

A further advantage of my invention comes from the fact that the sealing, notwithstanding it efiects a very perfect gas-tight seal of the edges surrounding the open ends of the rubber bellows member to the separable frame pieces, can not injure or rupture the bellows member itself.

I claim:

1. In combination with upper lower frame members of a mask leak tester adapted to be joined for free movement one away from the other with means for connecting the space between the frames with the inhalation tube of a therapeutic gas mask, an open-ended rubber bellows member between the frame members, an annular part at each end of the said bellows projecting laterally therefrom and contacting inn r portions of the respective frame mem c-rs, and removable means engaging latching po ions of said frame members and portions erally projecting parts of the bellows a 'l removably holding them in said cont for securing them to the respective frame member edg and sealing them gas tight thereto.

2. In core ination with upper and lower frame .bers of a mask leak tester adapted to be for free movement one away from the other and with means for connecting the space between the frames with the inhalation tube of a therapeutic gas mask, spaced concentric annular ribs extending from each frame member toward each other from the frame members, an open-ended rubber bellows having its ends contacting the respective frame members within the space between the ribs, and removable means engaging portions of said ends for removably holding them in said contact within the annular space for securing them to the respective frame members and sealing them gas tight thereto.

3. In combination with upper and lower frame members of a mask leak tester adapted to be joined for free movement one away from the other and with means for connecting the space between the frames with the inhalation tube of a therapeu ic gas mask, spaced concentric annular ribs extending from each frame member toward each other from the frame members, an ope-mended rubber bellows having its ends contacting the r-spective frame members within the space between the ribs, and snap rings adapted to be forced into said annular spaces and having portions thereof thereby caused to engage and compress the ends of the bellows member for removably holding the said bellows member to the respective frame members and sealing them gas tight thereto.

In combination with separable upper and lower frames of a, mask leak tester having means for connecting the space between the frames with the inhalation tube of a therapeutic gas mask, sets of spaced concentric annular ribs extending from each frame member toward each other one of said members being formed with an annular groove, an open-ended rubber bellows between the frame members having its edges about its open ends extending into the space between the ribs, and snap rings having projections thereon adapted to snap into the said groove and thereby engaging and compressing the ends of the bellows member for removably holding the said bellows member to the respective frame members and sealing said edge gas tight thereto.

5. In combination with separable upper and lower frames of a mask leak tester having means for connecting the space between the frames with the inhalation tube of a therapeutic gas mask, of spaced concentric annular ribs extending from each frame member toward each other one of said members being formed with an annular groove, open-ended rubber bellows between the frame members having its edges about its open ends extending into the space between the ribs, and snap rings having an unbroken annular head engageable with the ends of the bellows within said grooves and having thinner wall parts extending from the annular head and divided into segments forming individual spring members, and projections on said bellows adapted to snap into the groove, whereby the ends of the bellows will be removably secured and sealed to the respective frame members.

6. In combination with separable upper and lower frames of a mask leak tester having means for connecting the space between the frames with the inhalation tube of a therapeutic gas mask, a spaced concentric annular rib on each frame extending toward each other and each being formed with an annular groove about a sidewall, an open-ended rubber bellows having portions about its open ends in contact with the frame members adjacent said annular rib, and snap rings each having an unbroken head engageable with the end portions of said bellows and having thinner wall parts extending from the annular head and divided into segments forming individual spring members, and projections on said members adapted to snap into the groove, whereby the edges of the bellows member will be removably secured and sealed to the respective frame members.

'7. In combination with separable upper and lower frames of a mask leak tester having means for connecting the space between the frames with the inhalation tube of a therapeutic gas mask, a spaced concentric annular rib on each frame extending toward each other and each being formed with an annular groove about a side wall, an open-ended rubber bellows having portions about its open ends formed with laterally extending projections contacting the frame members adjacent said annular rib, and snap rings each having an unbroken head engageable with said annular projection at the ends of said bellows member, said rings having thinner wall parts extending from the annular head and divided into segments forming individual spring members, and projections on said members adapted to snap into the groove, whereby the projections from the edges of the bellows member will compressed and the bellows member thus secured and sealed to the respective frame memxers.

S. In combination with separable upper and tower frames of a mask leak tester adapted to be joined for free movement one away f om th other, a central opening in the upper frame member adapted for connect the space between the frames with the inhalation tube of a therapeutic gas mask, an open ended rubber bellows removably c nnected in gas-tight relation with the two frames so as to surround said openings, a peg on the lower frame extendin through said opening past the plane of the top surface of the upper frame when the frames are held together, and a swinging latch pivoted to the out. icle top of the upper frame and adapted to engage a notch in said extended portion of the peg for holding the two frames together 9. A leak detector for a demand type mask having a hose connected thereto, and a hose coupling on said hose, said detector comprising a casing having an opening through the top thereof, a bottom cover on said casing, a bellows attached to said casing at one end thereof and to said bottom cover at the opposite end thereof, the opening in said casing opening into the said bellows, and means to secure the hose coupling in said opening so that the hose connects with the interior of the bellows.

J AY A. I-IEIDBRINK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 682,183 Etheridge Sept. 10, 1901 987,667 Bickley Mar. 21, 1911 1,221,733 Henderson Apr. 3, 1017 FOREIGN PATENTS Number Country Date 113,882 Great Britain Sept. 12, 1918 177,033 Great Britain Mar. 23, 1922 693,045 Germany Oct. 31, 194.0

4,575 Great Britain 1881 

